Colorado Springs Utilities line crews restore power quickly and safely while working on energized lines.
Some linemen may only get to work on energized conductors once in a blue moon, but at Colorado Springs Utilities (Springs Utilities), field workers work on energized lines daily as a way to restore power quickly and safely to their 415,000 residents.
This commitment to power quality and reliability has paid off in the utilities' response to outages. Springs Utilities' System Average Interruption Duration Index (SAIDI) dropped from 36.6 minutes in 2006 to 31.43 minutes in 2008. For 2009, it climbed up to 49.07, but this is still well below the country average of 90 to 120 minutes.
To keep the lights on for their customers, the line technicians often employ live-line work methods. Here is how the utility is improving its reliability while keeping their workers safe in the field.
Turn Up the Heat
At Springs Utilities, line technicians work on energized conductors daily to maintain 1,000 miles of overhead and 2,300 miles of underground wire. Oftentimes, the line technicians work hot when doing energized pole replacements and transferring stages from old poles to new poles on the new feeders.
During these projects, the line technicians use insulated blankets and insulated rubber guts, and instead of doing bare-hand work, they perform rubber gloving and hot sticking.
In addition, the line technicians are working live on large projects, such as line rebuilds, as well as smaller maintenance jobs like changing out energized cross-arms.
Communication is Key
While working hot boosts productivity, it also presents safety issues. To ensure that the line workers work safely on the energized equipment, Springs Utilities linemen are required to attend a tailboard discussion. During this meeting, the line workers discuss all of the possible hazards as well as the emergency procedures.
During these safety talks, the utility ensures that all of the field workers are on the same page and understand the complexity and challenge of the energized work. During these open discussions, all of the line workers share their input.
Before working on an energized conductor, however, they also take another precaution. They write the exact address of the work location on a magnetic sign at the job site. That way, if someone gets injured, they will know exactly where to direct the emergency-response team. When an accident occurs, a lineman's mind could go blank, so it's always better to be prepared and be conscious of safety.
Work as a Team
Another way in which the line crews keep the lines of communication open is by having a minimum of two qualified line workers in the air and one qualified observer on the ground at all times. At Colorado Springs Utilities, it's critical for these three, or often four, team members to be focused on their job at hand to make sure everyone goes home safely.
The two line technicians in the air stay in constant communication with the person on the ground. If the person on the ground doesn't like what he or she sees, then the line technician will immediately stop work. This constant back-and-forth communication ensures that the linemen are working one phase at a time. For that reason, Springs Utilities mandates that there are qualified eyes and ears on the ground and in the air at all times when working live.
In addition, the linemen properly maintain their personal protective equipment. The field workers change out their rubber goods every three months and do a visual inspection daily. If gloves are damaged, then they are immediately returned to the Tool and Apparatus Shop for replacement.
The field workers also have their hot sticks tested annually. To ensure that they work properly, the line professionals keep them clean and dry in their line trucks.
The line professionals also protect themselves against hazards by wearing flame-retardant, long-sleeved shirts and pants. The linemen wear shirts with a minimum of an 8 calorie rating, as well as safety glasses and hard hats. The type of FR clothing that they wear depends on what part of the system they are working on during that specific day.
Energized Work Methods
Since personal protective equipment will only provide so much protection, the line workers also need to follow stringent safety guidelines such as checking the second point of contact. If the linemen are working on one phase, they must cover up adjacent phases, neutrals and grounds so they're not going phase to phase or phase to ground.
To protect the line workers, Springs Utilities' electric system is updated with instant trip relays, which will reduce the arc flash. Anytime the crews work energized, the line technicians notify distribution control. Also, this allows the line technicians to get a “hot line hold,” so they can put the circuit on one shot that they are working on. That way, they will get an instantaneous trip when they are working hands on. Some of the benefits are that if something happens, distribution control will know the exact address of where they are working. In addition, this work method prevents another line worker from closing a circuit back in on a line worker.
By employing these tools and techniques, Springs Utilities linemen are not only reducing outage times and improving reliability, but they're also ensuring that they can go home safely at the end of each day.
Justin Mitchell (firstname.lastname@example.org) is a line crew supervisor for Colorado Springs Utilities, Colorado. He has been with the company for 13 years.